In a single liquid processing unit (a liquid processing apparatus) in which a liquid processing is performed on a semiconductor wafer (hereinafter, referred to as a “wafer”) serving as a substrate by supplying various processing liquids, an alkaline or acidic chemical liquid is supplied to a wafer surface that is rotating to remove dusts or natural oxides from the wafer surface. The chemical liquid remaining on the wafer surface is removed by a rinse liquid. When the supply of the rinse liquid is stopped while rotating the wafer, the remaining rinse liquid is scattered, so that the wafer is dried. Here, a recovery cup (a cup body) is provided around the wafer to recover the processing liquid, and the liquid processing is performed under a clean atmosphere in which a downflow (a descending air flow) is formed towards the recovery cup.
Meanwhile, a swirling flow is generated above the rotating wafer to flow from a central side towards an outer peripheral side while swirling towards a rotational direction of the wafer. Since mists or vapor containing the chemical liquid remain around the recovery cup in some cases, the components thereof may be blown up by the swirling flow generated above the wafer, and re-attached to the dried wafer, thereby causing contamination.
Here, Japanese Patent Laid-Open No. 2010-192686 discloses a substrate processing apparatus in which a partition wall is provided to vertically partition a processing room accommodating a substrate holding unit and a cylindrical cup surrounding a periphery of the substrate holding unit such that the inside of the processing chamber is divided into smaller sections to enhance replacement efficiency of the mists scattered from the cup into the processing chamber (see ibid., paragraphs [0008] to [0010], and FIG. 1).
However, Japanese Patent Laid-Open No. 2010-192686 fails to disclose a method of suppressing contamination of the substrate which is caused by the above-mentioned swirling flow when the mists remain around the cup.